During the processing of silicon substrates in the manufacture of microelectronic circuits, many different tools may be employed for performing processes on the substrates. Various handling devices, such as robotic arms, may also be employed for moving the substrates between stations at which processing steps are performed. Each movement between stations entails a corresponding handling time required for performing the movement.
Generally, the various processes performed on a substrate must be executed in a particular, sequential order, and thus a process cannot be commenced on a substrate until a preceding process has been completed and the substrate has been delivered to a new process station. It is therefore generally desirable to reduce the handling time between successive stations in order to maximize the throughput of substrates while providing sufficient time for the execution of each process step. One way to reduce handling time is to reduce the number of movements (e.g., picks and places) that each handling device is responsible for performing. However, it is also generally desirable to minimize the number of handling devices that are involved in a process stream in order to reduce cost and complexity within a manufacturing environment. The layout, configuration, and sequencing of a substrate processing system are therefore important in order to optimize the throughput of substrates.